What is a Coil Pack? Everything you Need to Know

When it comes to the ins and outs of your vehicle, you may not know every part and piece. If you’re attempting to fix up your vehicle yourself, you’ll need to know about the parts in your vehicle that are less common than brakes or the engine. A coil pack is one important among those parts.

What Is a Coil Pack?

A coil pack is an electronically controlled collection of ignition coils. It is regulated by your vehicle’s internal computer and is an important component of any modern car. If your coil pack is faulty or fails entirely, it can cause the engine to misfire because your spark plugs are not receiving the proper voltage. This electronically controlled coil pack is made up of ignition coils all directed by the internal computer. The purpose of the coil pack is to build up energy and then release it as needed.

The ignition coil (also called a spark coil or induction coil) expands the battery’s voltage into thousands of volts needed to create the spark in your plugs to ignite the fuel. Today’s ignition coil systems use something called a “power transistor” to provide pulses that reach the ignition coil. 

The Energy Process of the Coil Pack

Ignition coils make up the larger coil pack. The ignition coil itself is an iron core that is surrounded by twin coils of copper wire. The coil pack contains a magnetic circuit which means that the iron core doesn’t form a closed energy loop. The energy within the magnetic field is transferred to the plug.

In personal vehicles, small coils are used with one coil per spark plug. Coils can be mounted atop spark plugs, and when this occurs is called a “direct ignition” plug. The spark that is generated because of the high voltage occurs within the spark plugs. The spark plugs then deliver the electrical current from the ignition to the engine’s combustion chamber. Then, the spark plugs can light the compressed fuel and air mixture with the created electrical spark, which keeps the combustion pressure level in the engine correct.

One common reason that an ignition coil might be failing is because of a gap in the spark plugs.

Signs of Coil Pack Issues


A vehicle backfire is an unmistakable issue. The frighteningly loud noise and shaking will most certainly clue you into any issues. A lurch, black smoke, or strong blast will scare you into looking for whatever is wrong with your vehicle. While low fuel pressure can sometimes be the cause here, faulty ignition coils can affect the ignition of your spark plugs which in turn cause misfirings, backfires, and more.

Stalled Engine

Abrupt starts, stops, and idling can make driving an obnoxious pain, as well as making it frightening and dangerous. If your coil pack starts to fail, your car might stall. Failing coil packs will send irregular sparks to the plugs, which will, in turn, make an uneven electrical charge and disrupt the smoothness of your running engine. 

A Lowered Fuel Economy

When your coil pack is not providing the proper energy to the spark plugs, your car will have to burn more fuel than usual to keep up with it. The only way to keep your vehicle running is if it contributes extra fuel. If you notice exceedingly poor gas mileage, you may have an issue with your coil pack and ignition coils.

Trouble With Engine Starting

If you have an issue starting your engine at all, you may think the cause is the battery or other similar issues. On rare occasions, it’s actually the coil pack that is causing the problem. If your vehicle has a “wasted spark system,” the car can run if a couple of the ignition coils are faulty, but you’ll notice difficulty in starting and a lack of smoothness with the engine.

Observing the Symptoms of a Faulty Coil Pack in Your Nissan

When the coil pack in your Nissan fails, it can be very frustrating and force you to seek out a lot of trial-and-error solutions. Make sure you check your spark plugs first, and if the issue cannot be resolved there, see if it’s your coil pack.

The most reliable way to find out if your coil pack is faulty is by utilizing a scan tool that can count the misfires of your cylinders. Scanner tools can give you the comprehensive information you need to discover what the issue is with your Nissan. This is a quick way to diagnose the faulty coil pack problem.

There is a somewhat easier test you can perform that may let you know that your coil pack is faulty: use an ohmmeter to check the primary secondary resistances of each coil. Remember, this test isn’t completely accurate. Still, you can use it to check the ohms range of your coil pack, measuring the primary resistance at the 10 ohms range. You will need to attach the leads to the center prong of the connector on each of the coils. 

If this sounds like too complex a step, check in with your local auto parts store or auto mechanic and have them do the test for you using their personal scan tools. If you’re looking for Nissan Parts in Canada, PartsAvatar can help you find the best coil pack replacement for your car.

How Much Does This Cost?

While the ignition coil and coil pack needs are dependent on the make and model of your car, the range shouldn’t set you back too much. Cheaper coils are in the $75 range while others can get up to as much as $300. The labor costs to get it professionally done will be around $50-$100 an hour, another reason why replacing the coil pack of your Nissan yourself is enticing for many people.

We hope this gives you a good idea of what your coil pack does, the issues surrounding it, and everything you need to diagnose the problems and get it replaced should you suspect that your coil pack has become faulty.